Amblyopia, the most common cause of monocular visual impairment in children, affects 2-3% of the general population. Traditionally, amblyopia is treated using an adhesive eye patch to cover the fellow eye. However, child compliance is low for this form of treatment because the patch is uncomfortable and creates a social stigma for the child. The purpose of this study is to test the efficacy of a more child-friendly novel intermitten occlusion therapy (IO Therapy) glasses. Our Specific Aims: (1) To assess the efficacy of IO Therapy for severe amblyopia; (2) To characterize objective compliance of IO Therapy with a high-tech microsensor. This proposal is the first study to determine the clinical effectiveness of IO Therapy as a novel therapeutic approach for treating severe amblyopia. The findings from this proposal will lead to: 1) a more child-friendly and customizable form of amblyopia treatment; 2) a characterization of individual objective compliance, enabling us to develop a patient- centered strategy of IO Therapy. This new direction is consistent with President Obama`s Precision Medicine Initiative in 2015.